The retinoblastoma susceptibility gene encodes a nuclear phosphoprotein associated with DNA binding activity

摘要: The human gene (RB) that determines susceptibility to hereditary retinoblastoma has been identified recently by molecular genetic techniques. Previous results indicate complete inactivation of the RB is required for tumour formation. As a 'cancer suppressor' gene, thus functions in manner opposite most other oncogenes. Sequence analysis complementary DNA clones demonstrated long open reading frame encoding hypothetical protein with features suggestive DNA-binding function. To further substantiate and identify protein, we have prepared rabbit antisera against trypE-RB fusion protein. purified anti-RB IgG immunoprecipitates doublet apparent relative mass (Mr) 110,000-114,000. specific protein(s) are present all cell lines expressing normal mRNA, but not detected five examined. can be metabolically labelled 32P-phosphoric acid, indicating it phosphoprotein. Biochemical fractionation immunofluorescence studies demonstrate majority located within nucleus. Furthermore, retained eluted from DNA-cellulose columns, suggesting associated binding activity. Taken together, these imply product may function regulating genes cell.